docs: def save(self, file_path):
          """Save ddy object as a .ddy file.
  
          args:
              file_path: A string representing the path to write the ddy file to.
          """
          # write all data into the file
          # write the file
          data = self.location.ep_style_location_string + '\n\n'
          for d_day in self.design_days:
              data = data + d_day.ep_style_string + '\n\n'
          write_to_file(file_path, data, True)